Origin:
A native of Europe and now common throughout North America, where it is a weed problem in nurseries and landscape, as well as in pastures due to its irritating properties to livestock that graze it.
Biology:
An annual weed that germinates in fall to early spring and propagates from seeds. It has a strong, unpleasant odor when the foliage is crushed, and contact with human skin may cause blistering or dermatitis. Livestock that eat the plant may get irritation of their mucous membranes and the milk from dairy animals that feed on it may have a strong, unpleasant flavor.
Identification:
The mature plant can grow to 3 feet tall as a bushy, heavily branched clump. Stems are thin and smooth and not particularly strong, allowing them to bend or sag. The leaves are compound pinnate, being divided several times into thin lobes. Flower heads are typically daisy-like, with yellow disc and long white ray flowers in a widely opened fashion. The head is usually around an inch in diameter and grows as a single flower head at the end of the long stalk
Characteristicts Important to Control:
Annual weeds easily removed by hand, but seeds may germinate early in the fall, so control and removal should be done early in the season.
